Tube bending apparatus



June 28, 1960 R. B. BERANEK TUBE BENDING APPARATUS 4 Sheets-Sheet 1 Filed Sept. 21, 1955 Aim I N VEN TOR. P0001. PH Bpucs BUM/Y5K A T TORNEVS June 28, 1960 R. B. BERANEK TUBE ssmamc APPARATUS 4 Sheets-Sheet 2 Filed Sept. 21, 1955 4 Sheets-Sheet 3 Filed Sept. 21, 1955 INVENTOR. Fun 01. PH BRUCE Bum/ix 5M/ TH, [)Lsmd Kam f9 7 TOENEVS TUBE BENDING APPARATUS Rudolph Bruce Beranek, Columbus, Ohio, assignor, by mesne assignments, to American Radiator & Standard Sanitary Corporation, New York, N.Y., acorporation of Delaware Filed Sept. 21, 1955, Ser. No. 535,640

9 Claims. (Cl. 153-45) This invention relates to a tube bending apparatus, and particularly to an apparatus for bending fill-equipped heat exchange tubes.

One embodiment of the invention includes an arcuate bending die and a movable bending pad adapted for engagement with a fin-equipped tube and movable through an are so as to bend the tube around the die surface. An abutment element is provided for preventing any undesired bowing of the straight tube portions during the bending operation. The abutment-element includes at least one tooth which is adapted to tightly fit between fins on the tube. An edge of the tooth abuts against the conduit portion of the tube so as to space the fin edges from the abutment element and thereby prevent deformation of the fin edges during the bending operation. The tooth is of substantially the same thickness as the fin spacing so as to prevent any axial movement of the tube such as would vary the bend arc and/or bend location.

The bending pad engages against a considerable length of the tube fins in order to prevent any bow inthe tube, and in order to distribute'the bending pressure and minimize the possibility of fin deformation. Thethrust means for the pad preferably takes the form of a fluid cylinderoperated lever. The lever necessarily describes a difierout are than the bending pad in order that relative longitudinal sliding of the pad and tube fins be maintained as small as possible. Accordingly the pad is rotatably mounted relative to the thrust means, and an adjustably positioned abutment means is provided for limiting relative rotatable movement of the pad and lever in accordance with the length of arc necessary to effect the bending operation. The extent to which the tube is bent is determined by the length of the arc taken by-the bending pad, and the pad arc is determined by adjustment of the abutment means. By a simply effected adjustment of the abutment means it is therefore possible to control the extent of the tube-bending operation.

In order for the bending apparatus to be commercially practicable it must be of such construction as to permit quick loading and unloading of the tubes. In one embodiment of the present invention the bending die is mounted for rotary movement toward and away from the toot -.equipped abutment element. When the die is positioned away from the abutment element a tube can be inserted into the apparatus, and whenthe die is moved to a position adjacent the abutment element the tube is locked in the apparatus ready to be bent. The rotary mounting for the die permits quick and easy die movement so as to facilitate loading and unloading of the tubes. 1

One object of the invention is to provide a bending apparatus for fin-equipped tubes, wherein the fin edges are prevented from being deformed during the bending operation.

Another object is .to provide a bending apparatus wherein the extent or amount of the bending operation can be controlled by a simply efiected adjustment.

Anotherobject is to provide a tube bending apparatus atenr O ice 2,942,644 Patented June 28, 1960 wherein thebend canbe formed at any of an indefinite number of locations along the tube length.

Another object is toprovide a tube bending apparatus wherein bowing of the tube is prevented at points remote from the bend areas.

Another object is to provide a tube bending apparatus wherein the tubes can be quickly loaded and unloaded.

Other objects of this invention will appear in the following description and appended-claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate correspondingparts in (the several views.

In thedrawings:

Fig. 1 is a top plan view of one embodimentof the invention showing a tube in position prior to the bending operation,

Fig. 2 is a top plan view of the Fig. 1 embodiment showing a tube in-position after the bending operation,

Fig. 3 is a bottom plan-view of the Fig. 1 embodiment showing elements thereof'in full lines prior to the bending operation and dotted lines subsequent to the'bending operation,

Fig. 4 is a sectional view on line 4-4 in Fig. 1,

Fig. 5 is a sectional view on line 5-5 in Fig. 1,

Fig. 6 is a sectional view on line 6-6 in Fig. 1,

Fig. 7 is a sectional view on line 7-7 in Fig. 2, and

Fig. 8 is a sectional-view on line 8-8 in Fig. 1.

Fig.9 is an enlarged-view of a portion of the structure shown in Fig. 1.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseolq y or terminology employed herein is for the purpose of description and not of limitation.

In the drawings there is shown a bending apparatus 1 including two planar-aligned table tops 2 and 3. Tops 2 and 3 are supported by two longitudinal bars 4 and 5 which are fixedly secured on a stand 6.

Stand 6 includes a horizontal frame formed by four interconnected angle irons 7 through 10. Angle irons 7 through 10 are fixedly supported onfour vertical legs 11 through 14.

Top 3 is fixedly secured on bars 4 and 5, andtop 2 is adjustably mounted on bars 4 and 5 for movement in the directions of arrows 15. In order to guide top 2 in its arrow 15 movement there are provided in said top a rectangular groove 16 in registry with bar 4, and a rectangular recess 17 in registry with bar 5.

Mechanism is provided for immovably retaining top 2 in any of several adjustedpositions on bars 4 and 5. This mechanism includes two blocks 18 and 19 secured'to bar 4 and angle iron 10 by 'bolts 20. Block 19 is provided with a threaded bore which meshes with a threaded rod 21. A nut 22 prevents turning ofrod 21 in the threaded bore. Rod 21 clearingly extends through a bore 23 in block 18. The only function of block 18 is as a-support for rod 21. Top 2 carries a block 23 which is provided with a through bore 24 loosely encircling rod 21. Nuts 25 and 26 are threaded on rod '21 for retaining block 23 (and top 2) in any adjusted position along bar 5. The adjustment is eflected'by turning out 25 or 26 on rod 21, moving block 23 into abutting engagement with the turned nut (by sliding top 2 along bars 4 and 5), and turning the other nut into clamping engagement against block 23.

Apparatus -1 includes two bending dies 27, each of which is mounted for rotatable movement on its respective tabletop bymeans of a-bolt 28. A crank 29 is-pro- 'abutsagainst face 42;

7 .table top.

' Each element 31 includesa pluralityiofteethn. [The depth ofteeth 32 in the direction of arrows 33 (see Fig.

1 is greater than the'radius 34 (see Fig. 6) of-fins 35 formed on heat exchange tube, 36. As a result the tin edges 37 are. prevented from contacting "the. abutment element, and thefins are prevented from beingdeformed during the bending operation- Each of teeth 32 are of substantially the same thickness (in the arrow direction) as the fin spacing so'that when the teeth extend r bending operation rod. 48 is in the Fig. 3 full line position with pads 38 and 39 in their Fig. 1 positions. Dies 27 are in their Fig. 1 positions. The apparatus is loaded by moving a tube 36 in the direction of arrow 63 through the space between dies 27 and abutment elements 31 until the end of the tube strikesfstop44, and thereafter moving the tube, laterally in the. direction of arrow 64 until the edges of teeth 32 contact the 'tube wall. Cranks 29 are then rotated through one half revolutions so as to bring dies 27 into their Fig. 2 positions. I

Energization of icylinders .49 by a valve-controlling pedal meansnot shown causes pads 39- and 40 to be moved from their Fig. .1 positions to their Fig. 2 posiinto the spaces between the fins (asin Fig. 1) axial movement of tube 36, is prevented.

In order to bend tube 36 around dies 27 there areprovided two bending pads 38 and-39." Each of these pads.

takes-the form of a longitudinalbar 40 having a concave. tube-engaging face 41 and a free face 42. Pad 39, is provided with a longitudinally extending guide element '43 on which is slidably positioned a tube-stop 44 (see Fig. "8).

V 'Aset screw45 holdss'top '44 in any adjusted'position along pad 39.? 1 The adjusted position of stop 44 determines the location of the formedbend in tube 36.v It

will be noted that each pad is elongated so as'to engage Y 1- i sists the reaction forceand prevents, further movement a substantial portion'of the tube length. ,In. this manner the force applied .to each tube fin'is comparatively small so as to prevent ;fin deformation during the tube-bending operation.

The thrust means for eachof pads 38. and 39 takes the form of a lever 46 fulcrumed on the respectiveone of tops Zand 3 at point'47. One end of each lever 46 is pivotally connected at point 56 to the piston'rod 48 of a fluid-cylinder 49.; Each of cylinders 49 is pivotally mounted at point 50 on the underside of its'respective table top.

Each lever 46 is. connected to its bending pad by nutbolt means 51, 52 ,(see .Figs. 6 and 8). A sleeve 53 encircles bolt 52 and extends through an arcuate slot'54 formed in the respective table top. Slot 54 is centered at the lever fulcrum point 47. Movement of piston rod 48 in the direction of arrow 55 (by the entrance of .pressure fluid into cylinder 49) causes lever 46 to move from its full line position to'its dotted line position so as to carry its bending pad from the Fig. 1 position to the Fig. r

2 position. The pivotal mounting of cylinder 49 compensates for the change in position of pivot 56 relative to the cylinder axis. 7

The pivotal connection between sleeve 53 and the retioned an abutment plate 58. Sleevei53 is slightly longer 'spective bending pad is effected through an ear 5'7 inte- C than the combined thickness of the table top (2 or 3) and v V ear*57.1 As a result, when bolt 51 is tightened down against plate '58 elements 51; 52, 58, 53 and 46 are clamped together for movement as a unit around point 47. The respective bending pad is free for rotationrela tive to sleeve 53.

Each of plates 58 has a face 59 inregistry withfree face 42 of bar 40. In the Fig. 1 position face 59 is spaced from face 42, and in the Fig. 2 position face 59 forcibly through each of lugs'60, and a nut 62 is provided for retaining each bolt in any desired adjusted position. Bolts '61 are adjusted so as to engage bars 40 and position them tio'ns. The'pads describe different arcs than levers 46 but the rotatable mounting at 53, 57 permitsrotary movement of each pad relative to its lever 46 so as to allow the pad to move toits Fig. 2 position. When the pad arrives at its Fig. 2 position portion of tube 36 is wrapped against die surface 30, and :portion 65 ofbar 40 is therefore prevented from any further movement in the direction ofarr'ow 67; The force from each lever 46 is transmitted to theresp'ective bar-.40 through bolt 52, and as bar 40 reaches the Fig. 2-position it becomes jammed between abutment; surface 59 and'tube portion 66. At thisitime lever 46' exerts a force inthe direction of arrow 68, and tube portiong66 exerts a reaction force on bar portion 65 in the direction of arrow 69. Abutof lever 46. Resistance to lever 46 movement is employed to actuate a valve (not ,shown)--'so as to reverse the fluid flow through cylinder 49 and return lever 46 to its Fig. 3 full line position. 'Cranks 29 may then be rotated through onehalf revolutions so as to permit removal of bent tube 36 from the bending apparatus.

, The extent or amount to which the tube is bent can be varied byiadjusting the position of plate'58. In Fig. 1 the angular spacing between surfaces .59 and 42 determines thelen gth of are which bar 40 can take before it becomes jammed between tube portion 66 and surface '59. By decreasing the angular spacing between surfaces 59 and 42 (in the Fig. 1 position) the length of are taken by bar 40 is decreased. Variation in the angular spacing between surfaces 59 and 42, may be accomplished by loosening nut 51, manually repositioning plate.58,'and thereafter retightening nut 51. The position of stop 44 on its bar 40 determines the location of the right hand bend relative to the right hand end of the tube, and the adjustment of tabletopz determines the spacing between the bends. I claim: 7 v 1. Tube bending apparatus comprising a bending die; abending pad; a lever for moving the pad through an are around the bending die; a sleeve engaging said lever and rotatably extended through. said pad; an abutment plate facially'engaging an end of said sleeve andhaving an abutment surface in operative registry 'with one face of the pad ata point spaced from the rotatable mounting are around the bending die; a sleeve engaging said lever and rotatably extendedthrough. said pad; 'an abutment plate facially engaging an end of said-sleeve and having an abutment surface in operative registry with one face of the pad; and releasable connector means lockingly extended through said abutmentplate, sleeve and lever;

parallelto'the axis of tube 36 when lever- 46 is in its Fig.3 position.

-. q s a n 9f appa atus 1 is such'that prior to the the releasable nature of the connector means serving to permit adjustment of the abutment plate relative to said one face of the pad, whereby when a tube is positioned between the pad and die a tube-bending operation can be continued until the pad forcibly engages the abutment plate.

3. Tube bending apparatus comprising a bending die; a first abutment member spaced from the die so as to permit snug placement of a tube therebetween; a bending pad having a longitudinal tube-engaging face positionable in alignment with the abutment member so as to engage a substantial length of the tube; a power-operated lever for moving the pad through an are around the bending die; shaft means fixedly carried by the lever and rotatably engaging the pad so as to permit rotary movement of said pad around the shaft means axis; and an abutment plate immovably carried by the shaft means and having an abutment surface in registry with a portion of the pad between the shaft means and bending die so as to limit rotary movement of the pad around the shaft means axis during the tube-bending operation.

4. Tube bending apparatus comprising an arcuate bending die; an abutment member spaced from the die to permit snug placement of a tube therebetween; a bending pad having an elongated tube-engaging face alignable with the tube-engaging portion of the abutment member; thrust means for moving the pad through an are offset from the arc of the bending die; and means movably mounting said pad on the thrust means for allowing the pad to move relative to the thrust means so as to have substantially its entire tube-engaging face conform with the tube throughout the tube-bending operation; the arc of the pad being located to substantially eliminate shifting of the pad along the tube during the tube-bending operation.

5. Tube bending apparatus comprising a bending die having an arcuate die surface; an abutment member spaced from the die to permit snug placement of a tube therebetween; a bending pad; thrust means for moving the pad through an are around an axis located adjacent the space between the die surface and abutment member to minimize shift of the pad on the work; and means rotatably mounting said pad on the thrust means for allowing the pad to maintain its position of engagement with the tube throughout the tube-bending operation.

6. Bending apparatus comprising an arcuate bending die; a bending pad having a substantially planar work engaging face of substantial length; thrust means for moving the pad through an are offset from the arc of the bending die such as to minimize shift of the pad on the work during the bending operation; means freely rotatably mounting said pad on the thrust means for allowing the pad to move relative to the thrust means so as to have substantially its entire work-engaging face conform with the work throughout the bending operation; and abutment means fixedly related to the thrust means and having an abutment surface in registry with the pad at a point spaced from the rotatable mounting means axis so as to limit rotary movement of the pad relative to the thrust means after extensive travel of the thrust means, whereby when work is positioned between the pad and die a work-bending operation can be continued until the pad forcibly engages the abutment means.

7. The combination of claim 4 and further comprising means for adjusting the abutment means relative to the thrust means to vary the arcuate extent of the workbending operation.

8. Apparatus for bending finned conduit comprising a bending die having an arcuate die surface; conduit-engaging abutment means including at least one tooth extended toward said die; said tooth having a depth greater than the fin radius and having a thickness substantially the same as the fin spacing; manually operable means movably adjusting said die to reduce and increase its spacing from the abutment means for facilitating insertion and clamping of a finned conduit; a bending pad; and thrust means for moving said pad through an are around the bending die.

9. Apparatus for bending finned conduit comprising a rotatably adjustable bending die having an arcuate die surface centered about its adjustment axis; abutment means including at least one tooth having a depth greater than the fin radius and having a thickness substantially the same as the fin spacing; said die having a surface in the plane of the die surface but located closer to the adjustment axis than the die surface to permit variation in the die-abutment means spacing for facilitating the loading of conduit into the apparatus; a bending pad; and thrust means for moving the pad through an are around the bending die to effect a conduit-bending operation.

References Cited in the file of this patent UNITED STATES PATENTS 165,804 Devine July 20, 1875 690,023 Hampson Dec. 31, 1901 1,141,166 Wirth June 1, 1915 1,263,301 Wheeler Apr. 16, 1918 1,379,858 Gail May 31, 1921 1,456,598 Jackson May 29, 1923 2,414,387 ONeil Jan. 14, 1947 2,482,617 Green Sept. 20, 1949 2,636,537 Redman et a1. Apr. 28, 1953 FOREIGN PATENTS 650,680 France Sept. 25, 1928 415,206 Great Britain Aug. 23, 1934 1,006,656 France Jan. 30, 1952 

